ES2926189T3 - Tensioning device with adjustment mechanism and procedure for adjusting the torque of the tensioning device - Google Patents

Abstract

The invention relates to a holding device (2) for a traction mechanism, comprising: a base element (3); at least one clamping arm (4, 6), which is rotatably mounted about an axis of rotation (A4, A6) relative to the base element (3) and has a tensioning pulley (5, 7), which is rotatably mounted in a bearing carrier (17) of the clamping arm (4, 6); spring means (8) for spring-loading the clamping arm (4, 6), wherein the spring means (8) extends between a first spring support (9) of the clamping arm (4) and a second support spring (10) of the clamping device (2) around the axis of rotation (A4, A6), in which the clamping device (2) additionally has an adjustment mechanism (11) for adjusting the first spring support (9) in relation to the bearing carrier (17) of the tension pulley (5) in a circumferential direction around the axis of rotation (A4, A6). (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Tensioning device with adjustment mechanism and procedure for adjusting the torque of the tensioning device

The invention relates to a tensioning device for a traction drive as well as a method for adjusting the torque of such a tensioning device. A traction drive, also called a traction drive or continuously variable transmission, is a transmission, in which the torque is transmitted between two or more shafts with the help of a drive means. A traction drive usually comprises an endless traction means and at least two wheels embraced by it, one of which can function as an input and the other as an output of the traction means.

In particular, a distinction is made between force-driven and positive-drive traction drives. In the case of power-driven traction drives, the torque is transmitted by frictional forces acting on the contact surface between the belt and the pulley. In the case of form-fitting traction drives, ie chain drives or toothed belt drives, the torque is transmitted by means of wheels with a corresponding form-fitting profile to or from the drive means.

Traction drives in the form of belt drives are used in particular in internal combustion engines of a motor vehicle to drive auxiliary units, a first pulley being placed on the crankshaft of the internal combustion engine and driving the belt. Other pulleys are associated with auxiliary units, such as the water pump, alternator or air conditioning compressor, and are rotatably driven by the belt drive. Between the crankshaft and the adjacent unit in the belt running direction, usually the generator, the slack leg is formed. In this case, in order to ensure sufficient wrapping of the belt around the pulley, the belt is pre-tensioned by means of a tensioning pulley of the tensioning device.

EP 2 128489 A2 discloses a tensioning device for a belt drive with a starter generator. The clamping device has a housing in which two clamping arms are mounted so that they can pivot about a common pivot axis. The tension arms are supported against each other by spring means. With the drive pulley mounted on the starter-generator, the housing can be mounted because in an annular area surrounding the drive shaft of the starter-generator it is arranged without contact with respect to the starter-generator.

From EP 2573423 A1 a belt tensioning device is known which has a base body with a tensioning arm pivotally mounted thereon. The belt tensioning device is designed in such a way that in the assembled state the pivot axis of the tensioning arm is arranged within the outer diameter of the drive pulley.

From DE 102015211 227 A1 a traction means tensioner for a traction drive of an internal combustion engine is known. The traction means tensioner comprises two tensioning arms, which can rotate relative to each other and each have a tensioning pulley, a spring unit, which tensions the two tensioning pulleys towards each other, as well as an actuator for rotate the tension arms towards each other. The actuator is designed as an electric motor that can be activated during operation to regulate the tension pulleys in a specific way.

From DE 3905218 C1 an adjusting unit for adjusting the belt tension of the drive belt of a motor vehicle is known. The adjustment unit has a tensioning element, which is designed in the form of a pinion, and a complementary tensioning element in the form of a rack, with which the tensioning element engages. By turning the tensioning element, the alternator pivots with respect to the vehicle engine and is thus adjusted in the plane of the transmission belt.

US 2008/070730 A1 describes a device for tensioning a flexible drive element. The device, with a pair of opposed contact elements, is in contact with an upper and a lower branch of the flexible actuating element. The device comprises a connecting element in the form of a spring clip, for bringing the contact elements together and positioning the contact elements at a selected distance from each other, to provide a predetermined tension to the flexible actuating element.

Belt drives are subject to static strand force oscillations, which are caused by production tolerances in belt length, diameter tolerances and pulley position relative to each other, and tensioner spring torque tolerances. of strap This applies to conventional belt tensioners with one tension arm as well as swing arm belt tensioners in belt-driven starter-generator applications. Due to the static fluctuations of the branch forces it is necessary to design the components of a belt drive robustly for a wide range between minimum and maximum branch force. For slip-free power transmission, relatively high branch forces are maintained.

From here, an objective of the present invention is to propose a tensioning device for a traction drive, which allows a reduction of the branch forces of the traction drive or a design of the belt drive so that the branch forces are lower. . Furthermore, the present invention is based on the object of proposing a corresponding method for adjusting the torque of such a tensioning device.

One solution is a tensioning device for a traction drive, comprising: a base body for connection to a stationary component; at least one tension arm, which is pivotably mounted relative to the base body about a pivot axis, with a tension pulley, which is rotatably mounted on a bearing support of the tension arm; spring means for elastically biasing the tensioning arm, the spring means extending between a first spring bearing of the tensioning arm and a second spring bearing of the tensioning device on the pivot axis; and characterized by an adjustment mechanism for adjusting the first spring bearing with respect to the tension pulley bearing support in the circumferential direction about the pivot axis, so that in the assembled state of the tensioning device the angle between the first spring support and the second spring support with respect to the pivot axis and thus the spring pretensioning force of the spring means.

An advantage of the tensioning device is that the adjustment mechanism allows an adjustment or variation of the branch force of the traction drive. This is achieved in that the first spring support can be moved in the circumferential direction with respect to the bearing bracket or the tension pulley connected to it. In this way, the circumferential length between the first spring support and the second spring support is also varied, so that the spring biasing force is varied. The specification in the circumferential direction is intended to include in particular any regulating movement that has a component in the circumferential direction. The branch force applied to the traction means can be limited to the extent necessary for slip-free power transmission, so that friction losses can be correspondingly reduced, which has a favorable effect on the drive efficiency. strap. The second spring bearing is associated with a component of the belt tensioner, relative to which the (first) tensioner arm can pivot. In this case, it can in particular be an additional (second) tension arm or the base body.

Thus, in the assembled state of the tensioning device, the angle between the first spring bearing and the second spring bearing with respect to the pivot axis of the tensioning arm is varied. In the assembled state of the tensioning device, the tensioning pulley is held stationary relative to the component, on which the spring means are supported. The traction drive is configured for torque transmission between two or more shafts with the aid of an endless drive means. In particular, the traction drive can be designed as a belt drive, a toothed belt drive or a chain drive.

The adjusting mechanism is configured to adjust the first spring bearing with respect to the bearing support, or the tension pulley mounted thereon, in the circumferential direction about the pivot axis. For this, the adjusting mechanism can have an actuator rigidly connected to the spring support and a support element rigidly connected to the bearing bracket, the actuator being guided so that it can be adjusted relative to the bearing. support element in the circumferential direction about the pivot axis, as well as a drive element for regulating the actuator with respect to the support element. With rigid connection it is meant in particular that the indicated parts cannot move with respect to one another and that, in particular, they can be made in one piece. For the configuration and arrangement of the actuator, the support element and the drive element, different possibilities are considered, for example the following.

According to a first embodiment, the drive element can be rotatably attached to the tensioning arm and can be configured for rotation with a drive structure. The drive structure of the drive element can cooperate with the complementary structure of a complementary component connected to the bearing bracket for common movement, specifically in such a way that a rotation of the drive element and the connected drive structure with the itself in a rotation-resistant manner gives rise to a circumferential movement of the tensioner arm with respect to the bearing bracket in the circumferential direction about the pivot axis. According to a first possibility, the drive structure can be designed in the form of a toothed structure, which cooperates with a toothed segment of the complementary component, the complementary component being an upper cover disc for the tensioning pulley. In this regard, a rotation of the toothed structure gives rise to a particularly linear movement of the complementary component and of the bearing support connected to it. According to a second possibility, the drive element can have an eccentric surface structure as the drive structure, which cooperates with a complementary surface of the complementary component, the complementary component being an upper cover disk for the tension pulley. The eccentric surface structure can be designed, for example, in the form of an eccentric adjusting curve, so that by turning the actuating element, an adjustment of the bearing bracket relative to the clamping arm takes place. It applies to both possibilities that the bearing bracket can have an axial through opening extending longitudinally in the circumferential direction, through which a fastening element such as a screw can be inserted to connect the tension pulley with the tension arm. The elongated through opening allows, with a rotation of the drive element, a circumferential movement of the bearing bracket with respect to the tensioner arm.

According to another embodiment, the drive element can be firmly connected to the bearing bracket, and the bearing bracket can be connected in a rotation-resistant manner to a lower cover disk for the tension pulley, the bearing structure being formed drive on the lower cover disk in the form of an eccentric surface structure, and the complementary structure being formed on the tension arm in the form of a complementary surface, on which the eccentric surface structure rests.

In the force transmission path between the drive element and the actuator, retaining means can be provided, which are designed to hold the actuator in defined positions with respect to the support element. The position of the retaining means, which can also be called a retaining mechanism, is in principle any position within the force transmission path. By force transmission path is meant in this context all components which are located between the actuating element and the actuator for the transmission of force.

According to one embodiment, the adjusting mechanism can be configured in such a way that the first spring support and the tension pulley can be adjusted relative to each other by up to 10° relative to the pivot axis. This regulation range should in any case be large enough to adjust the branch forces taking into account all the position and manufacturing tolerances of the components that influence the branch forces to the desired extent. To be more precise, provision can be made in particular for the first spring bearing and the tension pulley to be adjustable, starting from a central starting position, by up to ± 5° relative to the pivot axis. In this way it is favorably achieved that the spring means can be varied or adjusted from the central position in both directions. That is, branch forces can be increased or decreased as required.

The adjustment mechanism is preferably designed in such a way that the adjustment occurs at least essentially in the circumferential direction. This includes in particular that the adjustment takes place on an arc of a circle or a straight line approximately tangential to the pivot axis. According to a preferred embodiment, a stop is formed between the first spring support and the spring means, the adjustment mechanism being designed in particular in such a way that the stop can be moved within a range starting from an initial position. angle of up to ± 10° with respect to a tangent in the circumferential direction about the pivot axis (A). In this regard, the tangent can be defined as a perpendicular to the radius from the pivot axis to the stop. Instead of the stop, another element connected to the tension arm can also be considered as a reference point. By adjusting the spring support essentially in the circumferential direction, the effective direction of the pretensioning forces acting from the tension pulley on the traction means essentially does not change.

The spring means is configured and arranged to bias the at least one tension arm in the circumferential direction. At least one spring, ie one or more springs, which preferably extend around the longitudinal axis, can be provided. The spring can be designed, in particular, as a bending spring, which extends a radial distance in the circumferential direction about the pivot axis of the tension arm. By bending spring is meant in particular a spring which, under load, is essentially forced to bend. The bending spring extends in the circumferential direction about the pivot axis between the first spring support and the second spring support by a circumferential extension of, in particular, less than 980° (three turns), preferably less than 720° (two turns), possibly less than 360° (one turn). In this regard, the radius of the bending spring may vary along the circumferential extension. Examples of bending springs include a clamp spring, which extends in the circumferential direction preferably less than 360° about the pivot axis, or a spiral spring, which can extend more than 360° and/or less than 980° about the pivot axis. For a compact construction, it is favorable if the ratio of the nominal diameter of the coil spring to the axial length of the coil spring, in the installed state, is greater than 4.0, in particular greater than 5.0.

The configuration and arrangement of the second spring support depends on the type of belt tensioner, which can be designed as a one-arm tensioner or a two-arm tensioner. In the case of a single-arm clamp, exactly one clamp arm is provided, which is elastically supported in the circumferential direction via the spring means on the base body. In this embodiment, the second support surface, on which the spring means bear in the circumferential direction, is correspondingly associated with the base body.

A two-arm tensioner has two tension arms, namely a first tension arm with a first tension pulley and a second tension arm with a second tension pulley, the two tension arms being supported by spring means relative to each other in the circumferential direction. The second tension arm applies the traction means with the second tension pulley. The two clamping arms can be mounted relative to one another or relative to the base body such that they can pivot about their own pivot axis or about a common pivot axis. In this embodiment with two tension arms, the second support surface, on which the spring means bear in the circumferential direction, is associated with the second tension arm, so that the two tension arms are supported through the spring means in the circumferential direction relative to each other elastically.

Two-arm tensioners are used in belt drives in which a starter generator is integrated as an auxiliary unit in the belt drive, i.e. an electric motor, which, depending on the operating state, can be operated as a starter (starting motor). starter) or alternator (generator). In normal or engine operation, the pulley on the crankshaft is the drive pulley, while the starter generator as well as the remaining units are driven. In cranking or cranking operation, the starter generator drives the crankshaft via the corresponding pulley to start the internal combustion engine. In this type of belt drives with starter generator as an auxiliary unit, there is a changeover between motor operation on the one hand and starter operation on the other, between the pulling leg and the slack leg on both sides of the starter generator pulley. It is therefore necessary to provide spring-loaded tensioning pulleys for the two mentioned strands and thus two tensioning arms, one of which in each case acts on the slack strand under spring force, while the other is pushed back. by the taut traction line.

According to one embodiment, the base body and/or the at least one tension arm can have an opening, into which a drive shaft and/or pulley of a unit can enter in the assembled state. The base body can be designed as a steel component, in particular as a sheet metal forming part. In this way, advantageously a high resistance and rigidity is achieved with little contribution of material. The base body can have one or more fastening segments, which in particular protrude like a flange from the segment surrounding the opening, through which the drive shaft is guided. It is favorable if several fixing points are provided at which the base body can be connected to the unit.

One solution further consists of a method for adjusting the torque of a tensioning device, which has a tensioning arm pivotable relative to another component of the tensioning device about a pivot axis with a tensioning pulley, spring means, by means of which the tensioning arm is supported with respect to the component in the circumferential direction, as well as an adjustment mechanism to regulate the tensioning arm with respect to the tensioning pulley, with the following steps: determine a theoretical torque, which the tensioning device must present in the state mounted; measuring the actual torque of the tensioning device by a pivot angle of the tensioning arm when pivoting the tensioning arm with respect to the component, on which the spring means is supported; pivoting the tension arm relative to the component to a theoretical pivot angle, at which the theoretical torque is applied; and placing a mark representing the theoretical pivot angle on the tensioning device.

With the procedure it is possible to adjust the spring pretension of the tensioning device always to the nominal torque value. In other words, the tensioning device can be adjusted in the installed state to the smallest possible branch forces required for slip-free power transmission in the belt drive. With the tensioning device and the method, static branch force tolerances can be compensated, which can be caused, for example, by manufacturing torque, position and spring tolerances. Procedure and device are part of a uniform concept, so that all features of the procedure can be transferred to the device, and vice versa, all features of the device to the procedure. In particular, the method can be carried out with the tensioning device according to the invention, which can have one or more of the configurations mentioned above.

For example the theoretical torque can be calculated or specified by the end user. The calculation of the theoretical torque can be produced, for example, based on power data of the belt drive such as the torque to be transmitted by the traction means, degree of wrapping on the drive pulleys, type of traction means, nominal torque of the unit etc The measurement of the torque of the tensioning device can take place by means of a suitable measuring device, which detects the spring torque from the pivot angle of the tensioning arm. From this a torque-tension angle characteristic curve can be derived for the respective tensioning device. In this connection, the torque generated by the tensioning device increases correspondingly as the pivoting of the tensioning arm with respect to the spring support increases due to the increase in spring pretension. By means of the torque-tension angle characteristic curve, a corresponding torque is associated with each pivot angle of the tension arm. To adjust the desired theoretical torque, the tensioner arm is moved to the corresponding pivoted position or angular position. In this position, a mark is applied to the tensioning device, which allows the tensioning arm to be pivoted reproducibly, without a new torque measurement, to the desired angular position.

The mark can be designed, for example, in the form of an optical and/or haptic perception mark, which can be applied, for example, by painting, etching, heat treatment by means of lasers or the like. In particular, provision can be made for a first marking element to be associated with the clamping arm and a second marking element to be associated with the component, relative to which the clamping arm can pivot, which are axially opposed to one another in the desired theoretical angular position.

At a later stage the tensioning device is installed on a belt drive. For this, the tensioning device is attached to a stationary component, the belt is arranged around all drive pulleys, and the tensioning pulley is biased against the belt under spring pretension. It is now possible to adjust the tension arm by means of the adjustment mechanism with respect to the tension pulley, until the mark representing the theoretical pivot angle or the marking elements are aligned with each other. The adjusting mechanism is fixed in this adjustment position. The desired theoretical torque is now applied.

In the following, preferred embodiments will be explained using the drawing figures. In these, FIG. 1A shows a belt tensioning device according to the invention in a first embodiment in an axial view; FIG. 1B shows the belt tensioning device from FIG. 1A in a perspective view;

FIG. 1C shows the belt tensioning device from FIG. 1A with an adjustable tensioning pulley in an exploded view;

figure 1D, the adjustable tensioning pulley of the belt tensioning device of figure 1A as a detail in longitudinal section;

figure 1E, the adjustable tensioning pulley of the belt tensioning device of figure 1A in different ^{adjustment positions (P0, P1 , P2 );}

FIG. 2 a torque characteristic curve (Ispring) for determining a theoretical angular position for adjusting the spring pretension for a belt tensioning device according to the invention;

FIG. 3 a belt drive with the belt tensioning device from FIG. 1;

FIG. 4A a belt tensioning device according to the invention in a second embodiment in an axial view; FIG. 4B shows the belt tensioning device from FIG. 4A in a perspective view;

FIG. 4C shows the belt tensioning device from FIG. 4A with an adjustable tensioning pulley in an exploded view;

figure 4D, the adjustable tensioning pulley of the belt tensioning device of figure 4A as a detail in longitudinal section;

FIG. 5A shows a belt tensioning device according to the invention in another embodiment in an oblique perspective view from below, with an adjustable tensioning pulley in an exploded view; figure 5B, the adjustable tensioning pulley of the belt tensioning device of figure 5A as a detail in longitudinal section;

FIG. 5C shows the adjustable tensioning pulley of FIG. 5B in cross section along the adjustment contour;

FIG. 6A shows a belt tensioning device according to the invention in a further embodiment in an oblique perspective view from the front;

figure 6B, a detail of the belt tensioning device of figure 6A in a perspective side view of the adjustment mechanism;

FIG. 7 shows a belt tensioning device according to the invention in a further embodiment in an oblique perspective view from above;

FIG. 8A shows a belt tensioning device according to the invention in a further embodiment in an exploded perspective view;

Fig. 8B, the belt tensioning device of Fig. 8A in a top view;

Fig. 8C shows the belt tensioning device of Fig. 8A in a side view; Y

8D shows the belt tensioning device from FIG. 8A in a top view in a partially sectional representation.

Figures 1A to 1E, which will be described below together with Figures 2 and 3 as a whole, show a belt tensioning device 2 according to the invention in a first embodiment. The belt tensioning device 2 comprises a base body 3, a first tensioning arm 4 with a first tensioning pulley 5, a second tensioning arm 6 with a second tensioning pulley 7 and a spring 8, through which the two tensioning arms 4 , 6 are elastically supported relative to one another in the direction of rotation. The spring 8 extends between a first spring support 9 of the first tension arm 4 and a second spring support 10 of the second tension arm 6 by a circumferential length L8. This An adjusting mechanism 11 is provided for adjusting the first spring bearing 9 with respect to the first tension pulley 5 in the circumferential direction. By means of the adjustment mechanism 11, which will be referred to further below, the circumferential length L8 between the two spring supports 9, 10 and thus the torque or the spring pretension acting between the tension pulleys 5, 7 can be varied. .

The base body 3 can be attached to a stationary component as a unit. The unit can in principle be any machine that is part of the belt drive, ie in particular any auxiliary unit driven by the main engine of the motor vehicle such as generator, water pump or the like. For its connection to the stationary component, the base body 3 has several fastening segments 47 distributed around the circumference, which in particular are designed in the form of radially outwardly protruding flange lugs with holes, through which screws can be inserted. for attachment to the stationary component. The two tensioning arms 4, 6 of the belt tensioning device 2 are rotatably mounted relative to each other or relative to the base body 3 via corresponding bearing means about a pivot axis A4, A6. The base body 3, the first clamping arm 4 and/or the second clamping arm 6 are preferably designed as steel components, which in particular can be made of sheet metal by forming.

The first tension arm 4 is pivotally mounted about a first pivot axis A4 by means of a first bearing. The second tension arm 6 is pivotally mounted about a second pivot axis A6 by means of a second bearing. In this case, the two bearings are arranged coaxially with respect to one another, ie the two pivot axes A4, A6 coincide. In principle, however, it is also conceivable for certain applications that the two pivot axes can be arranged parallel to or eccentrically relative to one another.

The spring 8 extending in the circumferential direction with respect to the pivot axes A4, A6 counteracts a relative pivoting movement of the two tension arms 4, 6. The two tension arms 4, 6 can rotate relative to each other to a limited extent by the interposed spring 8 and can rotate freely together with the spring 8 relative to the base body 3 about the axes A4, A6, ie 360° and more. It is provided that in the assembled state of the belt tensioning device 2 the pivot axes A4, A6 lie within the opening 41 of the base body 3.

The tension arms 4, 6 each have a carrier segment 12, 13, which protrudes radially outwardly from an annular bearing segment 14, 15 of the respective tension arm 4, 6. On the carrier segment 12, 13 is fixed in each case a corresponding tension pulley 5, 7 and by means of the corresponding bearings 16, 16' is rotatably mounted about axes of rotation A5, A7 parallel to the pivot axes A4, A6. The bearing 16' for the second tension pulley 7 is mounted in a bearing housing rigidly connected to the carrier segment 13. The bearing 16' is fastened by means of a screw 27' to the carrier segment 13. Washers 19, 19 ' upper and lower prevent dirt from entering the bearings 16, 16' of the tension pulleys 5, 7.

A particularity of the present embodiment consists in the configuration of the first tensioning pulley arrangement, which comprises the first tensioning pulley 5 and the adjustment mechanism 11, in a compact construction unit.

The first tension pulley 5 is mounted on a bearing support 17 of the first tension arm 4 so that it can rotate about a rotation axis A5. The bearing support 17 can be adjusted with respect to the tension arm 4 by means of the adjustment mechanism 11 and fixed in the desired position. By a movement of the tension arm 4 relative to the bearing bracket 17, the first spring bearing 9 connected to the tension arm moves correspondingly relative to the tension pulley 5 in the circumferential direction. Depending on the direction of movement, this results in an expansion or contraction of the spring 8, so that the spring force and thus the torque generated by the belt tensioner 2 can be varied.

The adjustment mechanism 11 comprises an actuator 18, which is connected to the spring support 9, a support element 19, which is connected to the bearing support 17, and an actuating element 20 for adjusting the actuator with respect to the element support. The support element 19 is supported on the one hand on the actuator 18 and on the other hand on the drive element 20 in the circumferential direction, which also includes indirect support.

In the present embodiment, the actuator 18 is designed as a projection projecting axially from the tensioning arm 4, which has a guide contour 22 extending in the circumferential direction. The bearing bracket 17 engages in the guide contour 22 with a mating complementary contour 23 therewith, so that the bearing bracket 17 is guided relative to the tension arm 4 in the circumferential direction or tangentially relative to the axis. pivot A4. In this case, the guide contour 22 and the complementary contour 23 are designed according to the tongue-and-groove principle, without being limited to it.

The bearing bracket 17 is connected at its upper end to the bearing element 18, in particular by means of a form-fit connection. To this end, the bearing bracket 17 has latching means 24, which are latched in a corresponding opening of the support element 19 in a rotation-resistant manner. Through the form-fit connection, it is achieved that the bearing bracket 17 moves together with the support element 19, when the latter is controlled by means of the drive element 20. In this case, the support element 19 is designed in the form cover disk, which has a rack segment 25 on an upper end surface, which cooperates with a corresponding toothed structure 26 of the drive element 20. The cover disk 19 is arranged coaxially to the bearing bracket 17 and thus also coaxially to the tension pulley 5 and covers the bearing 16 upwards, to prevent the entry of dirt. An additional cover disk 48 is provided on the underside of the tension pulley 5 .

In this case, the drive element 20 is designed in the form of a gear nut, which has an external toothing as drive structure as well as an external contour for introducing a torque, in particular an external hexagon. The drive element 20 has a central passage opening 43, through which a fixing element 27 is inserted. The fixing element 27, which is designed in the form of a screw (without being limited to it), is guided through elongated through opening of bearing bracket 17 and threads into tension arm 4. In this way, drive element 20 is rotatably mounted on screw 27.

A rotation of the drive element 20, via the intermeshing teeth 25, 26, results in a relative movement of the support element 19, the bearing bracket 17 connected to it and the tension pulley 5 connected to it. with it relative to the actuating element 20 and to the tensioning arm 4 connected with it via the fixing element 27 along the guide 22, 23. The movement occurs approximately in the circumferential direction about the pivot axis A4. In Fig. 1E different adjustment positions are shown, in which it is possible to adjust the tension pulley 5 from a central position with respect to the fixing element 27. A central adjustment position is shown in the middle. If from here the drive element 20 is rotated counterclockwise (left representation), then the clamping element 27 and with it also the clamping arm 4 connected to it are correspondingly pushed on the pivot axis A4 clockwise away from idler pulley 5. Spring 8 expands, thereby increasing the torque generated by the spring. If, on the other hand, the drive element 20 is rotated clockwise from the center position (right illustration), then the clamping element 27 and with it also the clamping arm 4 connected to it move clockwise. on the pivot axis A4 in the counterclockwise direction with respect to the tension pulley 5. The spring 8 closes, so that the torque generated by the spring is reduced.

The adjustment mechanism 11 will be designed in such a way that the adjustment interval between the two end positions P1, P2 is large enough to adjust the torque that can be generated from the belt tensioning device 2 taking into account all the position and manufacturing tolerances of the belt tensioner components to the desired size. For example, the adjustment mechanism 11 can be configured in such a way that the first spring support 9 and the tension pulley 5 can be adjusted relative to each other by an angular range b of up to 10° relative to the pivot axis A4. In particular, it is provided that the first spring support 9 and the tension pulley 5, starting from a central initial position (P0), can be adjusted up to ± 5° with respect to the pivot axis A4 to opposite end positions (P1, P2). In this way it is possible to increase or decrease the torque of the spring 8 and thus the branch forces as required.

In this case the adjustment direction is defined by the guide 22, 23 between the adjustment element 18 and the bearing support 17, which in this case has a straight design and extends tangentially to the pivot axis A4. It goes without saying that the regulation can also take place non-rectilinearly, in particular in the form of an arc, also deviating from a tangent. Preferably the adjustment mechanism 11 is designed in such a way that the adjustment occurs at least essentially in the circumferential direction. This refers in particular to the fact that a reference point of the first clamping arm 5, for example a stop 28 for the spring 8 or the threaded hole 29 for the fixing screw 27, starting from a starting position (P0), has a direction of movement that, in an axial view, lies within an angular range g of up to ± 10° with respect to a tangent T0 about the pivot axis A4. In this regard, the tangent T0 can be defined as a radius R perpendicular to the pivot axis A4 to the reference point.

In order to be able to carry out the adjustment of the theoretical torque of the belt tensioner 2 in the final assembly in the belt drive in a simple manner, according to a preferred embodiment of the method, a presetting is carried out during the assembly and testing of the belt tensioner 2. This is carried out will be explained below with reference to the belt tensioner 2 according to figure 1 with the help of figures 2 and 3.

For the reproducible setting of a target torque, which can also be called target torque, the actual torque M of the tensioning device 2 is first measured by a pivot angle a of the tensioning arm 4 when pivoting relative to the second tensioning arm 6. obtains a torque-tension angle characteristic curve Ispring for the respective tensioning device 2, as shown schematically in Figure 2. It can be seen that the torque M generated by the tensioning device 2, which essentially corresponds to the spring torque, increases from correspondingly as the pivot angle a of the tension arm 4 increases in the direction of the second spring support. In this connection, by means of the torque-tension angle characteristic curve (Ispring), a corresponding torque M can be associated with each relative pivot angle a. To adjust the desired theoretical torque, the tensioner arm 4 is moved to the corresponding pivoted position (P0) or angular position (aset). In this position, a marking 30 is applied to the clamping device 2, which allows the clamping arm to be pivoted reproducibly without a new torque measurement to the desired angular position and to be set to the desired nominal torque Mset. Mark 30 is shown in Figure 1B; it can be recognized that it is made in the form of a stripe, which has a segment in the first arm tensor 4 and a segment on the second tensor arm 6, the two line segments aligning in the theoretical angular position aset. The theoretical torque is determined, for example, based on the power data of the belt drive.

In a later stage, the tensioning device 2 is installed on a belt drive 32, as shown by way of example in Fig. 3. For this, the tensioning device 2 is placed on a stationary component, in this case on a drive. 33, the belt 34 is arranged around all the drive pulleys 35, 36, 37 and the tension pulley 5 is biased against the belt 38 under spring tension. The tension arm 4 can then be adjusted by means of the adjusting mechanism 11 with respect to the tension pulley 5, until the mark 30 representing the theoretical pivot angle aset is reached or the marking elements are aligned with each other. Now the desired theoretical torque Mset is applied. In this case the unit 33 is designed in the form of a generator (alternator). The housing 39 of the generator can be recognized which can be connected to a motor block. The belt tensioning device 2 is attached to the generator 33 on the front side. This is achieved by means of mounting flanges 47 distributed around the circumference, into which screws 40 can be inserted and which can be screwed with the housing 39 of the generator. . Furthermore, the endless belt 34 and the pulley 35 can be seen, which are connected to the generator drive shaft 33 in a rotation-resistant manner. The base body 3 or the belt tensioning device 2 is designed in such a way that, in the mounted state of the belt tensioning device 2 on the unit 33, the pivot axes A4, A6 of the tensioning arms 4, 6 are arranged inside the outside diameter of the drive shaft.

Figures 4A to 4D, which will be described as a whole below, show a tensioning device 2 according to the invention in a second embodiment. The present tensioning device 2 corresponds for the most part to the embodiment according to Figures 1 to 3, whereby reference is made to the above description for common points. In this respect, the same components or corresponding components have the same reference numerals, as in figures 1 to 3.

The present belt tensioner 2 according to FIG. 4 differs from the previous embodiment in the configuration of the adjustment mechanism 11, in particular the support element 19 and the drive element 20.

In this case, the drive element 20 is designed in the form of an eccentric nut, which has a drive structure 26 in the form of an eccentric surface, which is arranged eccentrically with respect to the through hole for the screw 27. The drive element 20 acts together with the support element 19 as a complementary component, which is designed in the form of an upper cover disc for the tension pulley 5. The cover disc 19 has a support surface 25, which is in contact with the eccentric surface 26 By turning the eccentric nut 20 the eccentric adjustment curve 26 moves along the support surface 25, so that the cover disc 19 moves with respect to the screw 27 relative to the pivot axis A4 approximately in the direction circumferential direction. Correspondingly, the bearing bracket 17, which is firmly connected to the cover disk 19, and the tension pulley 5 move with respect to the screw 27 and the tension arm 4 connected to it along the guide. 22, 23 formed between the bearing bracket 17 and the actuator 18. Depending on the direction of rotation of the eccentric nut 20, the eccentric adjustment curve 26, starting from a central adjustment position, can be rotated in intervals of greater or lesser radius, so that the spring 8 can be expanded or contracted correspondingly.

In particular in Fig. 4A it can be seen that a retaining means 31 is provided between the eccentric nut 20 and the cover disk 19. The retaining means 31 is designed by a retaining structure on an outer surface of the eccentric curve 26, in which the support surface 25 projecting radially through the range of rotation of the eccentric nut 20 can engage in partial steps producing a retention. Thus the eccentric nut 20 is held in defined positions with respect to the cover disc 19. Thus an undesired rotation after adjustment of the nominal tension angle aset is avoided.

As in the previous embodiment, the actuator 18 is designed as an axially protruding projection of the tensioning arm 4 with a guide contour 22 extending in the circumferential direction. The bearing bracket 17 engages in the guide contour 22 with a corresponding complementary contour 23, so that the bearing bracket 17 is guided relative to the tension arm 4 in the circumferential direction or tangentially relative to the pivot axis A4. The relative movement between the tensioning pulley 5 and the tensioning arm 4 occurs in this sense in a manner analogous to the previous embodiment, with which reference is made to its description.

Figures 5A to 5C, which will be described as a whole below, show a tensioning device 2 according to the invention in a third embodiment. The present tensioning device 2 largely corresponds to the embodiment according to FIG. 4, so that with regard to the points in common, reference will be made to the previous description of FIG. 4 and thus also to the description of FIGS. 1 to 3. In this connection, the same components or corresponding components are provided with the same reference numerals, as in figures 1 to 4.

The present belt tensioner 2 according to FIG. 5 differs from the previous embodiment in the configuration of the adjustment mechanism 11, in particular the actuator 18, the support element 19 and the drive element 20.

In this case the drive element 20 is designed in one piece with the bearing support 17. Torque input means in the form of an external hexagon are provided for the introduction of a torque in the drive element 20, without being limited thereto. . The drive element 20 has a through hole 43, through which the screw 27 is inserted for connection with the tensioning arm 4. The screw 27 and the carrier element 17 are arranged coaxially with respect to each other or to the axis of rotation A5. Screwed onto the lower end of the screw 27 is a nut 44, which is secured against rotation relative to the actuator 18, but is held in a displaceable manner along the guide structure 22 of the actuator 18 in the circumferential direction. to the pivot axis A4. In this regard, the external surface 23 of the nut 44 forms the complementary contour of the guide.

In this case, the support element 19 is designed as a lower cover plate and is therefore arranged below the bearing 16, or between the bearing bracket 17 and the actuator 18. The cover plate 19 has a drive structure 26 on it. eccentric surface shape, which is arranged eccentrically to the through-hole for screw 27. Cover plate 19 co-acts with actuator 18 as a complementary component, to adjust tension arm 4 relative to tension pulley 5. Actuator 18 is joined to tension arm 4 in one piece and has a support surface 25, which is in contact with eccentric surface 26 of cover disc 19. Cover disc 19 is connected to the rotation-resistant carrier element 17 or the actuation element 20 through form drive means 24.

By rotating the drive element 20, the eccentric adjustment curve 26 of the cover disk 19 moves along the bearing surface 25 of the actuator 18, stationary with respect to the tension arm 4, so that the actuator 18 moves relative to the cover disk 19 or screw 27 relative to the pivot axis A4 approximately in the circumferential direction. In a corresponding manner, the bearing bracket 17, which is firmly connected to the cover disk 19, and the tension pulley 15 move with respect to the adjusting element 18 and the tension arm 4 connected with it along the guide 22, 23 formed between the adjusting element 18 and the nut 44. Depending on the direction of rotation of the actuating element 20 and the cover disk 19 connected to it in a rotation-resistant manner, the eccentric adjusting curve 26, starting from a central adjustment position, it can be rotated in steps of greater or lesser radius, so that the spring 8 can be expanded or contracted correspondingly.

As can be seen in particular in FIG. 5C, retaining means 31 are also provided in the present embodiment. that the complementary surface 25 projecting radially through the range of rotation of the support element 19 can be engaged in partial steps producing a retention. Thus the cover disk 19 is held in defined rotational positions with respect to the adjusting element 18.

The actuator 18 has a guide contour 22 extending in the circumferential direction, which is designed in the form of an elongated recess. The nut 44 engages in the guide contour 22 with the corresponding complementary contour 23, so that the bearing support 17 is guided with respect to the tension arm 4 in the circumferential direction or tangentially with respect to the pivot axis A4. The relative movement between the tensioning pulley 5 and the tensioning arm 4 occurs in this sense in a manner analogous to the previous embodiment, with which reference is made to its description.

Figures 6A and 6B, which will be described as a whole below, show a tensioning device 2 according to the invention in another embodiment. The present tensioning device 2 largely corresponds to the embodiment according to FIG. 1, so that with regard to the points in common, reference will be made to the previous description of FIG. 1 and thus also to the description of FIGS. 2 and 3. In this connection, the same details or modified details are provided with the same reference numerals, as in the previous figures.

In the present embodiment, the adjusting mechanism 11 is not arranged in the region of the tensioning pulley, but rather in an area between the two tensioning pulleys 5, 7, offset circumferentially therefrom.

As in the previous embodiments, the adjusting mechanism 11 comprises an actuator 18, which is connected to the spring support 9, a support element 19, which is connected to the bearing support 17, and an actuating element 20. to regulate the actuator 18 with respect to the support element 19. The support element 19 is supported on the one hand on the actuator 18 and on the other hand on the actuating element 20 in the circumferential direction, which will also include indirect support.

In the present embodiment, the drive member 20 has a sleeve segment, with which the drive member 20 is rotatably mounted on a set screw 45, and a drive structure 26 in the form of an eccentric surface. The set screw 45 is fastened with a first end to the support element 19. At the opposite second end a screw thread is provided, onto which a clamping nut 46 is screwed. In the loosened state of the clamping nut 46 it is It is possible to rotate the drive sleeve 20 and the adjusting element 18 connected to it. By tightening the clamping nut 46, the drive sleeve 20 arranged between the nut 46 and the adjusting element 18 is fixed and thus secured against rotation. For the introduction of the torque, the drive sleeve 20 has an external hexagon, other torque contours also being possible.

Eccentric surface 26, which is disposed eccentrically to set screw 45, coacts ^{with adjusting element} 18 ^{as a complementary component to move it in the circumferential direction} relative to bearing element 18. Adjusting element 18 is designed in the form of annular segment that, through guiding means 22, 23; 22', 23', is guided with limited movement relative to the support element 19 in the circumferential direction. The annular segment 18, on one side opposite the guide, has an axial projection 25, which forms the complementary element, on which the eccentric adjustment surface 26 rests. For guidance in the circumferential direction, the annular segment 18 has a first guide element 23 in the form of an axial projection, which engages in a first oblong hole 22 of the support element 19, as well as a second guide element 23' offset circumferentially thereon, in the form of an axial projection, which engages in a second oblong hole 22' of the support element 19. The first guide element 23 is longer than the second and extends with a segment through the oblong hole 22 The protruding segment of the guide element 23 forms the first spring support 9, on which the spring 8 is supported with an end segment bent radially in the circumferential direction.

The support element 19 is an integral part of the first tension arm 4, which via the spring 8 rests elastically in the circumferential direction on the second tension arm 6, the first tension arm 4 being adjustable with the first spring support 9 by means of the adjusting mechanism 11 with respect to the second tension arm 5 and the corresponding second spring support 10 in the circumferential direction. By turning the drive sleeve 20, the adjusting curve 26 is rotated eccentrically relative to the complementary surface 25 of the ring segment 18, so that the ring segment 18 moves relative to the set screw 45 in the circumferential direction relative to the pivot axis A4. Correspondingly, the annular segment 18 and the spring bearing 9 connected to it move relative to the set screw 45 and the clamping arm 4 connected to it along the guides 22, 23; 22', 23' formed between the support element 19 and the annular segment 18. Depending on the direction of rotation of the drive sleeve 20, the eccentric adjustment curve 26, starting from a central adjustment position, can be rotated in intervals of larger or smaller radius, so that the spring 8 can expand or contract accordingly. The relative movement between the tensioning pulley 5 and the tensioning arm 4 occurs in a manner analogous to the previous embodiment, with which reference is made to its description.

Furthermore, in FIG. 6B, a marking element 30' can be seen, which is designed in the form of a triangle bent axially relative to the annular segment 18. After setting the desired angular position aset, in which the nominal torque Mset exists, during presetting a complementary mark 30 is made on the opposite tension arm 6 . Thus, during final assembly it is possible to adjust the nominal torque Mset in a simple way by turning the drive sleeve until the marking element 30' is facing the complementary marking 30.

Figure 7 shows a tensioning device 2 according to the invention in another embodiment. The present tensioning device 2 largely corresponds to the embodiment according to Fig. 4, to which description reference is made in an abbreviated manner with respect to common features like the description of Figs. 1 to 3. In this regard, the same details or modified details are provided with the same reference numerals, as in the previous figures.

The tensioning device according to the present embodiment has a single tensioning arm 4 with a corresponding tensioning pulley 5. The first spring support 9, as in the previous embodiments, is associated with the first tension arm 4. The second spring support 10 is associated with the base body 3 or formed on it (and not, as in the forms of previous embodiments, in the second tension arm).

With regard to all other details on construction and operation, the tensioning device according to Figure 7 corresponds to that of Figure 4, the description of which is referred to here in an abbreviated manner, including the description of Figures 1 to 3.

Figures 8A to 8D show a belt tensioning device 2 according to the invention in another embodiment. The tensioning device 2 shown is also, as in the tensioning device according to FIG. 7, a one-arm tensioner and largely corresponds to the embodiment according to FIG. 7, with reference to the description of the forms of embodiment according to FIG. 7 and thus also to the description of FIGS. 1 to 4 in abbreviated form with regard to the common features. In this respect the same details or modified details are provided with the same reference numerals, as in the previous figures.

The belt tensioning device 2 has a base body 3 in the form of a receiving housing for the spring means 8, which are designed as a spiral spring. A tension arm 4 is arranged on the base body 3 so that it can rotate about the pivot axis A4. The tensioning arm 4 carries at one free end and eccentrically to the pivot axis A4 the tensioning pulley 5, which is rotatably mounted on the bearing support 17 of the tensioning arm 4. The base body 3 can be fixed on a component stationary as an engine unit or block (not shown) or a component attached thereto. For fastening the base body 3, it has several radially outwardly protruding fastening segments 51, 52 with bores, through which screws or bolts can be inserted for fastening to the stationary component.

The spring means 8 are supported on the one hand in a first spring support 9 of the tensioning arm 4. In this sense, the first spring support 9 comprises a set screw 53, which is screwed into a threaded hole 50 of the arm. tensioner 4. The spring means 8 are supported essentially tangentially on the set screw 53. The set screw 53 has an internal hexagon 49, by means of which it is possible to screw the set screw 53 by means of a corresponding tool in the direction of rotation. a tangent T more or less deep in the threaded hole 50. In this way the tangential position of the first spring support 9, in particular of the point of contact between the set screw 53 and the spring means 8, varies with respect to the bearing bracket 17 and tension pulley 5.

The spring means 8 are supported tangentially on a second spring support (not shown here) arranged on the base body 3 and thus in the circumferential direction with respect to the pivot axis A4. When the tension arm 4 is stationarily attached to the base body 3 or the tension pulley 5 is stationary attached to the base body 3, such as in the mounted state of the belt tensioner 2 in a traction drive , the spring means 8 is prestressed in the circumferential direction to a greater or lesser extent. This is achieved in that by adjusting the set screw 53 and thus by adjusting the spring support 9 the length or the distance between the first spring support 9 and the second spring support varies in the circumferential direction.

Reference symbol list

2 belt tensioning device

3 basic body

4 first tension arm

5 first tension pulley

6 second idler arm

7 second tension pulley

8 spring

9 spring support

10 spring support

11 regulating mechanism

12 carrier segment

13 carrier segment

14 bearing segment

15 bearing segment

16, 16’ bearing

17 bearing bracket

18 actuator

19 support element

20 drive element

21 through opening

22 guide contour

23 complementary contour

24 means of hitch

25 support structure

26 drive structure

27 fastener

28.28' top

29 threaded hole

30 mark

31 means of retention

32 belt drive

33 unit

34 strap

35 pulley

36 pulley

37 pulley

38 strap

39 casing

40 screw

41 opening

42 opening

43 through hole

44 nut

45 grub screw

46 lock nut

47 fixing segment

48 disc cover

49 internal hexagon

50 threaded hole

51 fixing segment

52 fixing segment

53 grub screw

a, b, g angle

to axis

L length

m pair

position

R radius

T tangent

Claims (16)

1. Tensioning device for a traction drive, comprising: a base body (3); at least one tensioning arm (4, 6), which is pivotally mounted relative to the base body (3) about a pivot axis (A4, A6) and has a tensioning pulley (5, 7), which is rotatably mounted on a bearing support (17) of the tension arm (4, 6); spring means (8) for elastically biasing the tension arm (4, 6), the spring means (8) extending between a first spring support (9) of the tension arm (4) and a second spring support ( 10) of the tensioning device on the pivot axis (A4, A6), characterized by an adjustment mechanism (11) for adjusting the first spring support (9) with respect to the bearing support (17) of the tension pulley (5) in the circumferential direction about the pivot axis (A4, A6), so that in the installed state of the tensioning device, the angle between the first spring support (9) and the second spring support (10) with respect to the pivot axis (A4, A6) and thus the pretensioning force can be varied. spring of the spring means (8). Tensioning device according to claim 1, characterized in that the adjustment mechanism (11) has an actuator (18), which is rigidly connected to the first spring support (9), and a support element (19). , which is rigidly connected to the bearing bracket (17), the actuator (18) being guided in an adjustable manner relative to the support element (19) in the circumferential direction about the pivot axis (A4, A6). ), as well as a drive element (20) to regulate the actuator (18) with respect to the support element (19). Tensioning device according to claim 2, characterized in that retention means (31) are provided in the force transmission path between the actuating element (20) and the actuator (18), which are designed to hold the actuator (18) in defined positions with respect to the support element (19). Tensioning device according to one of Claims 1 to 3, characterized in that the first spring support (9) and the tensioning pulley (5) can be adjusted relative to each other by up to 10° relative to the pivot axis (A4, A6). ), in particular up to ± 5° starting from an initial position (P0). Tensioning device according to one of Claims 1 to 4, characterized in that a stop (28) is formed between the first spring support (9) and the spring means (8), a tangent (T0) being able to be defined through of the stop (28) as perpendicular to the radius (R) from the pivot axis (A4, A6) to the stop (28), the adjustment mechanism (11) being designed in such a way that the stop (28), starting from an initial position (P0), has a direction of movement that, in an axial view, is within an angular range ( g) of up to ± 10° with respect to the tangent (T0). Tensioning device according to one of Claims 1 to 5, characterized in that the bearing bracket (17) has an axial through opening (21) extending longitudinally in the circumferential direction. Tensioning device according to one of Claims 2 to 6, characterized in that the actuating element (20) is fixed to the tensioning arm (4) in a stationary and rotatable manner and has a drive structure (26), which cooperates with a complementary structure (25) of a complementary component (19) connected with the bearing support (17) for common movement, such that a rotation of the drive element (20) and the connected drive structure (26) with it in a rotation-resistant manner gives rise to a circumferential movement of the tensioner arm (4) with respect to the bearing bracket (17) in the circumferential direction about the pivot axis (A4, A6). (Figures 1 to 6) 8. Tensioning device according to claim 7, characterized in that the actuating element (20) has a toothed structure as actuating structure (26), which acts together with a toothed segment (25) of the complementary component (19), the latter being complementary component (19) an upper cover disc for the tension pulley (5). (Figure 1) Tensioning device according to claim 7, characterized in that the actuating element (20) has an eccentric surface structure as actuating structure (26), which cooperates with a complementary surface (25) of the complementary component (19), the complementary component (19) being an upper cover disk for the tension pulley (5). (Figure 4) Tensioning device according to claim 7, characterized in that the drive element (20) is firmly connected to the bearing bracket (17) and the bearing bracket (17) is connected to the bearing in a rotation-resistant manner. actuator (19), the actuator (19) being designed in the form of a lower cover disc for the tension pulley (5) and the drive structure (26) being formed on the lower cover disc in the form of an eccentric surface structure, the complementary structure (25) being formed in the form of a complementary surface on the support element (18), on which the eccentric surface structure is supported. (Figure 5) Tensioning device according to one of Claims 1 to 10, characterized in that the at least one tensioning arm (4, 6) and the base body (3) each have an opening (41, 42), in which a drive shaft and/or pulley (35) of a unit (33) can be inserted in the assembled state. Tensioning device according to one of Claims 1 to 11, characterized in that the spring means (8) are designed in the form of a bending spring, which extends in the circumferential direction about the pivot axis (A4, A6) between the first spring support (9) and the second spring support (10) and has a circumferential extension of, in particular, less than 980°, preferably less than 720°, optionally less than 360°. Tensioning device according to one of Claims 1 to 12, characterized in that only one tensioning arm (4) is provided, the second spring support (10) being associated with it, on which the spring means (8) are supported on the circumferential direction, to the base body (3). Tensioning device according to one of claims 1 to 12, characterized in that the at least one tensioning arm comprises a first tensioning arm (4) and a second tensioning arm (6), the first tensioning arm (4) being mounted in such a way which can pivot about a first pivot axis (A4) and having a first tension pulley (5) and the second tension arm (6) being mounted so that it can pivot about a second pivot axis (A6) and having a second pulley tensioner (7), and because the second spring support (10), on which the spring means (8) rest in the circumferential direction, is associated with the second tensioner arm (6), so that the two arms tensioners (4, 6) are supported via the spring means (8) relative to one another in the circumferential direction in an elastic manner. 15. Method for adjusting the torque of a tensioning device (2), according to one of claims 1 to 14, with the following steps: determining a theoretical torque (Mset), which the tensioning device (2) must have in the assembled state; measure the actual torque (M) of the tensioning device (2) by a pivot angle (a) of the tensioning arm (4) when pivoting the tensioning arm (4) with respect to the component (3, 6), on which they are supported the spring means (8); pivoting the tension arm (4) with respect to the component (3, 6) up to a theoretical pivot angle (aset), in which the theoretical torque (Mset) is applied; place a mark (30, 30') that represents the theoretical pivot angle (aset) on the tensioning device (2). 16. Method according to claim 15, characterized by the additional steps of: install the tensioning device (2) on a belt drive (32) and adjust the tension arm (4) with respect to the tension pulley (5) by means of the adjustment mechanism (11) until reaching the mark (30) that represents the theoretical pivot angle (aset).